I have 2 different customers with a DSX 40 saying the speaker phone fades out. When they talk for about 20-30 seconds it will just reinitialize. They each have a 22 button phone. It doesnt happen all the time its just very random.

Have you tried swapping phones / ports ?

By "resetting" do you mean the phone powers up / down , or just loses audio ?

The most common cause of problems with speakerphones, in general, is background noise that triggers the speaker cut-off, to prevent screeching. Try muting and see if incoming sound quality stays up.

I have swapped ports, phones, installed new jack and station wire. When I say initialize, it will actually show that in the display. It will lose power, just for that one phone, then power up. Everything else works perfect.

So it loses power only when its being used in speaker mode ?

Cable between 66 Block and Ksu input of the rj45-s feeding the KSU. ???

High joint connection ?

Skip - Yes. Just the one phone will reset while in speaker mode but it is random.

STS E - yes